Module 2: Genetics and environment + integumentary system

Question 1

What are the nucleotide pairs?

Answer 1

Adenine - Thymine, Guanine - Cytosine

Question 2

What are chromosomes?

Answer 2

Condensed DNA templates

Question 3

What is DNA?

Answer 3

Individual coding molecules

Question 4

What are genes?

Answer 4

Protein-specific DNA sequence code

Question 5

What are the proteins used in DNA replication?

Answer 5

• DNA helicase (template unzipping)
• DNA polymerase (nucleotide addition and proofreading)
• DNA ligase (seals off the new DNA)

Question 6

List the DNA mutations by the severity of protein alteration

Answer 6

Missense mutation (specific mispairing)
Nonsense mutaiton (codes the stop codon)
Frameshift mutation (insertion or deletion of a pair)

Question 7

What are the differences between diploid somatic cells and haploid gametes?

Answer 7

Diploid are body cells, n=46, go through mitosis
Haploid are sperm and egg cells, n=23 (individual chromosomes), go through meiosis

Question 8

What is polyploidy and aneuploidy?

Answer 8

Ploy: multiple of 23 chromosomes
Aneu: not a multiple of 23 chromosomes (ex trisomy 21 has 47 chromosomes)

Question 9

What are the characteristics of Turner syndrome?

Answer 9

X chromosome anomaly, n=45, 1% of fetuses survive, loss of paternal X chromosome
- Short stature
- Abnormal female genitalia
- Exogenous estrogen for secondary sexual development

Question 10

What are the characteristics of Klinefelter syndrome?

Answer 10

X chromosome anomaly, n=47, extra X chromosome
- male appearance & sterile
- small testes and female breast development
- Increased physical and mental alterations

Question 11

What are the 4 types of chromosome breakage?

Answer 11

• Deletion (smaller chromosome, loss of information ex Cri du chat syndrome)
• Duplication (duplication of a section of the chromosome ex Huntington’s disease)
• Inversion (swapped info)
• Reciprocal translocation (2 chromosomes that swap a part of each other ex Chronic Myeloid Leukemia)

Question 12

What is a phenotype?

Answer 12

The expression of a trait (outward appearance of organism)
Genotype + environment

Question 13

What are alleles?

Answer 13

Variants of genes (ex pair of alleles BB or Bb or bb)

Question 14

What is a genotype?

Answer 14

Refers to the pair of alleles, the genetic constitution of a person

Question 15

What is a polymorphism?

Answer 15

the presence of 2 or more variant forms of a specific DNA sequence that can occur among different individuals (ex CYP2D6)

Question 16

What happens when a red and a white flower have incomplete dominance alleles?

Answer 16

pink flower! (heterozygotes)

Question 17

What happens when a red and white flower have codominance?

Answer 17

Red and white flower!! (heterozygotes)

Question 18

Give an example of incidence

Answer 18

New cases of breast cancer in Quebec is 20/100 000 in 2018
(# of new cases in a timeframe, within a population)

Question 19

Give an example of prevalence

Answer 19

Number of smokers in Québec is 17% in 2018
(ratio of affected individuals at a specific time, based on existing and new cases added up)

Question 20

What is the difference between monozygotic and dizygotic twins?

Answer 20

Mono have 1 sperm and one egg, so they are genetic clones (identical twins)
Di have 2 sperms and 2 eggs (fraternal twins)

Question 21

What is epigenetics?

Answer 21

It modifies the expression pattern of some genes. It is influenced by environmental factors. Some epigenetic modifications can be transmitted to offspring

Question 22

What is the main constituent of skin, hair and nail cells?

Answer 22

Keratin

Question 23

What is continuous turnover of skin cells?

Answer 23

The time it takes for a cell to go from stratum basale all the way up and then shed

Question 24

What is found in the dermis?

Answer 24

Hair shaft, nerves, sweat and sebaceous glands, lymphatic and blood vessels, mast cells/macrophages/fibroblasts

Question 25

What is found in the hypodermis?

Answer 25

Adipose tissue and blood vessels. It connects the skin to muscles

Question 26

What causes male-pattern alopecia?

Answer 26

androgen-sensitive follicles

Question 27

What is alopecia areata?

Answer 27

A T-cell mediated autoimmune disease causing the chronic inflammation of hair follicles

Question 28

What could indicate hirsutism?

Answer 28

Endocrine disorders like polycystic ovaries, adrenal hyperplasia or tumours

Question 29

What is paronychia?

Answer 29

Infection of the cuticle (abcess may develop, moisture increased risk of infection. caused by strepto or staph)

Question 30

What is onychomycosis?

Answer 30

Infection of the nail plate (hyperkeratotic debris within the plate, shows yellow and elevated nail. caused by a fungal or dermatophyte infection)

Question 31

Explain the 4 degrees of frostbite

Answer 31

1st: superficial freezing of the epidermis 2nd: full thickness freezing (hypodermis and dermis) 3rd: deep and full-thickness + subcutaneous freezing (hypodermis, dermis and subcutaneous) 4th: Deep and full-thickness + subcutaneous freezing + gangrene (cells undergoing necrosis)

Question 32

What happens to hair with aging?

Answer 32

Lower count of melanocytes (responsible for pigmentation) and Langerhans cells (specialised macrophages) which lead to the loss of protection and hair color

Question 33

What happens to skin with aging?

Answer 33

Loss of elastin, collagen and fibroblast leads to the loss of elasticity and increases wrinkles

Question 34

What are the 4 stages of pressure injuries?

Answer 34

1: irritation of the skin 2: down to the soft tissues (fatty tissues, dermis) 3: reaches the muscles or other structures 4: bone is exposed

Question 35

What is the pathophysiology behind allergic contact dermatitis?

Answer 35

allergen contact on skin -> triggers immune cells -> T-cell activation + cytokines release -> inflammation

Question 36

What is the pathophysiology behind irritant contact dermatitis?

Answer 36

skin barrier compromised -> exposition to irritant -> inflammation in response to injury (injury is proportional to irritant concentration and exposure)

Question 37

What is the pathophysiology behind psoriasis?

Answer 37

Th17/IL-23 pathway hyperactivation -> extensive/constant skin inflammation -> keratinocyte hyperplasia + vasculature -> plaque formation

Question 38

What are the 4 risk factors for acne vulgaris?

Answer 38

Hyperkeratinization, increase of sebum production (from increased androgen/testosterone levels), increase proliferation of P. acnes bacteria, rupture of sebaceous follicle

Question 39

What is the pathophysiology behind acne vulgaris?

Answer 39

risk factor -> skin pore obstruction -> inflammation

Question 40

What is the pathophysiology behind acne rosacea?

Answer 40

chronic abnormal vasodilation -> erythema

Question 41

What are the common hallmarks of acne rosacea?

Answer 41

Photosensitivity, fibrosis and telangiectasia (flushing) and sebaceous hypertrophy

Question 42

What is the pathophysiology behind discoid lupus erythematosus?

Answer 42

UV light + altered immunity -> activation of self-reactive T&B cells -> formation of autoantibodies immune complexes (AIC) -> skin damage + vasculitis

Question 43

What is the pathophysiology behind herpes simplex?

Answer 43

virus infects epithelium cells -> latency in local dorsal root ganglion -> viral reactivation -> skin lesions

Question 44

What is the pathophysiology behind herpes zoster & varicella?

Answer 44

virus infects epithelium cells -> latency in local root ganglion -> viral reactivation -> skin lesions

Question 45

What is the pathophysiology behind Kaposi sarcoma?

Answer 45

immunosuppression -> latent HSV-8 opportunistic infection -> multilocal lesions & inflammation at blood vessels -> characteristics purple plaques & nodular lesions

Question 46

What is the pathophysiology behind Lyme disease?

Answer 46

tick bite -> bacterial invasion of tissues -> localized erythema migrans (T-cell mediated) -> systemic spreading -> secondary erythema migrans + complications

Question 47

What are the 3 stages of infections for Lyme disease?

Answer 47

1: localized erythema migrans (days after bite) 2: spreading of illness with neuralgias and neuritis/carditis (weeks) 3: late persistent can lead to encephalopathy and heart failure